Reactor Operations Engineer

About Radiant

Radiant is an El Segundo, CA-based startup building the world’s first mass-produced, portable nuclear microreactors. The company’s first reactor, Kaleidos, is a 1-megawatt, fail-safe microreactor that can be transported anywhere power is needed and run for up to 5 years without refueling. Portable nuclear power with rapid-deploy capability can replace similar-sized diesel generators and provide critical asset support for hospitals, data centers, remote sites, and military bases. Radiant’s unique, practical approach to nuclear development leverages modern software engineering to rapidly deliver safe, factory-built microreactors that use existing, well-qualified materials. Founded in 2020, Radiant is on track to test its first reactor at the Idaho National Laboratory this summer, with initial customer deliveries beginning in 2028.

About the Role
We are seeking a Reactor Systems Engineer to support the technical integration of a first-of-a-kind reactor. With no operating predecessor to copy and no mature supply chain, you will help ensure that design decisions across nuclear physics, thermal-hydraulics, controls, structures, materials, fuel, and licensing come together into a reactor that works safely and is delivered to customers on time.

This role is hands-on technically — you'll dig into thermal models, component specs, and subsystem designs — whi